Controller for electric motors



April 7, 1953 J. T. KENNEDY ET AL CONTROLLER FOR ELECTRIC MOTORSOriginal Filed May 15, 1946 Patented Apr. 7, 1953 CONTROLLER FORELECTRIC MOTORS John T. Kennedy, Wauwatosa, and Eivind U.

Lassen, Whitefish Bay, Wis., assignors to Cutler-Hammer, Inc.,Milwaukee, Wis., a corporation of Delaware Continuation of applicationSerial No. 669,776,

May 15, 1946.

1950, Serial No. 189,722

8 Claims. 1

This invention relates to controllers for electric motors, controllersembodying the invention being especially advantageous for motor drivenwashing machines although not limited to such application.

This application is a continuation of our application Serial No.669,776, filed May 15, 1946.

In the case of a washing machine comprising a rotary cylinder and anenclosing shell each provided with a door it is important for timesaving to provide for stopping with the doors in a close registeringrelation. Otherwise inching is required to bring the doors intoregistration, and the present invention has among its objects to provideimproved control means of the so-called automatic door spotting typewhich will effect close registering relation of the doors when thecylinder comes to rest, regardless of the rotary position of thecylinder when stopping is initiated.

Another object is to provide control for the aforementioned and otherapplications which will be accurate, reliable, expeditious and simple.

Another object is to provide control of the aforementioned type which inthe case of motor driven machines subjected to reverse operations willprovide for operation always in a given direction for door spotting,thereby to afford greater accuracy.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates diagrammatically one embodiment ofthe invention which will now be described, it being understood that theembodiment illustrated is susceptible of various modifications withoutdeparting from the scope of the appended claims.

Referring to the drawing, the same depicts a washing machine applicationof the control, the drawing illustrating diagrammatically a washingmachine W to be driven by a polyphase alternating current motor M. Themachine W is shown as comprising a cylinder I to be oscillated within ashell 2, the cylinder 1 having a door 3, and the shell having a door 4.The connection of the cylinder 1 to motor M is indicated by a brokenline, and as will later appear oscillation of the cylinder isaccomplished by reverse operations of motor M. As is customary, themotor M is provided with an electromagnetically controlled brake B, theconnection of the brake to the motor being indicated by a broken line.The brake B preferably is of the well known type which setsautomatically and which is releasable by an electromagnet H].

For a purpose hereinafter set forth the cylinder This applicationOctober 12,

l of machine W has mechanically connected thereto as indicated by abroken line a limit switch LS. The switch is operable by a cam H drivenby the cylinder I to momentarily disengage its contacts on eachrevolution of the cyllnder and in a given rotary position of thecylinder. Preferably the switch LS is of a well known design forintermittent opening only when the machine operates in forwarddirection, which may be assumed to be in clockwise direction. Forillustration the cam II is shown as coupled to a single tooth ratchetwheel l2 engageable by a pawl l3 on the cyclinder I, the arrangementbeing such as to effect drive of cam H by the cylinder only when thelatter rotates clockwise and only after the cylinder and cam haveassumed a given relationship. Thus it will be understood that switch LSis to be closed throughout counterclockwise rotation of cylinder I.

The motor M is adapted to be connected to supply lines L L and L forreverse operations selectively by suitable switches F and R, shown astriple pole electromagnetic switches. The reversing connectionscontrolled by switches F and R are of a well known type and hencerequire no description, said connections including in series with twoterminals of the motor respectively windings l5 and it of an overloadrelay OL.

The operating windings IT and 18 of switches F and R, respectively, areshown as being under the control of a suitable timer T comprising acontactor t movable alternately into engagement with contacts t and t byelectromagnetic operating means 15 This timer which may be of any one ofthe well known types tends by engagement of contacts t and t to energizewinding ll of switch F and alternatively by engagement of contacts t andt tends to effect energization of winding l8 of switch R.

In accordance with common practice in washing machine control thecontroller illustrated comprises two push button switches 29 and 2!included in control connections to lines L and L respectively. Also adoor switch 22 is included in the control connections to line L thisswitch being operatively connected, as indicated by a broken line, tothe door 4 of machine W, to be closed when and only when door 4 isclosed.

The means for accomplishing stopping and door spotting comprises inaddition to the limit switch LS aforementioned electromagnetic relays 25and 26, energizable by push button stopping or spotting switch 21. Aswill later be explained in greater detail, depression of the push buttonswitch 21 energizes both relays, relay 25 establishing for itself amaintaining circuit independent of push button switch 21, and relay 26establishing for itself independent of switch 2'! a maintaining circuitthrough limit switch LS. Response; of relays 25 and 26 effectsenergization of switch F independently of the timer T, and also effectscontinued energization of the releasing magnet Ill of brake B until thelimit switch LS is twice opened, its first opening being only effectiveto deenergize relay 26. The limit switch LS after opening then reclosesand during the momentary opening thereof 'certain of the contacts ofrelay 25 due to retarded opening maintain the switch F and the brakemagnet energized until the limit switch LS against opens. Then theswitch F is deenergized to, disconnect the motor from circuit, whereasat the same time the brake magnet H) is deenergized to. permit the brakeB to set to bring the motor and machine W to rest. When the switch R isenergized. at'the time relays 25 and 25respond said relays firstdeenergize'switch R and then energizeswitch F. It'will thusbe'seen thatas switch LS-must open twice for stopping and opens only when thecylinder is operating under control of switch F and is in a given rotaryposition accurate'automatic stopping with the doors 3 and 4 of machine Win a close registering relation may be reliably effected regardless ofthe rotary position of cylinder I when the stop switch 27 is pressed.

Also inasmuch-as the relay 25 upon responding opens contacts which mustbe reclosed prior to restarting, automatic restarting will be blockedby-the self-maintaining'relay 25. On the other hand; relay'25 maybedeenergized preparatory to restarting by opening of'the door 4 andconsequent opening of door switch 22, Orby opening either or both ofpush button switches and 2|.

Considering in further detail the means disclosed, the relay comprisestwo sets of normally engaged contacts and 3|, and two sets ofnormallydisengaged contacts 32 and 33, and an operating winding 34. Therelay 26 comprises normally engaged contacts 36,- two sets of normallydisengaged contacts 31 and 33, and an operating winding 39. The contacts87 of relay 26 have associated therewith a timing device such as adashpot 20 which has no effect on said contacts in closing upon responseof said relay, but

which effects delayed opening of said contacts upon deenergization ofsaid relay; The time element thus' provided for contacts 3'3 is pref-'-erably just enough tocover reliably the period required for opening andreclosing of the limit switch LS.

Upon closure of the doorswitch 22 and closure of the push buttonswitches 20 and 2| starting is effected, assuming relays 25 and 26 to bedeenergized. Circuit is completed from line L through switches 20 and22, and contacts 36 and 3| of relay 25 to and through the operatingmeans 23 of timer T, to and through contacts 42 of the overload relayand push button switch 2| to line L This effects operation of the timerand at'the same time release of brake B is effected by completion ofcircuit from contacts 30 of relay 25 to and through brake magnet It) toline L through contacts 42 of the overload relay and switch 2|. Thenwhen the timer contact t engages contact t circuit is completed fromcontacts 3! of relay 25 to and through said timer contacts and normallyclosed contacts 43 of switch R to and through the winding ll of switch Fto line L through the-overload relay contacts and switch 2|.Alternatively when the timer contact it engages contact t circuit iscompleted from contacts 3| of relay 25 to and through said timercontacts to and through the winding 8 of switchR to line L With theseconnections the machine W will be operated pending emergency stopping bythe operation of switch 20, 2|

' or 22 or normal stopping by operation of push button switch 21.

Operation of switch 2! completes circuit from the door switch 22.through the left hand pair of contacts'of switch 2! to and through thewinding 34 of relay 25to overload relay contacts 42. Additionally switch21 completes circuit through its right hand pair. of contacts to andthrough the winding'39 of. relay 26 to overload relay contacts 42..Contacts333 of relay 25 shunt the left hand pair of contacts of switch2! to render relay 25 self-maintaining, and contacts 38 of relay 26shunt the right hand pair of contacts of switch 21, establishing amaintaining circuit for winding 39 through limit switch LS. With re lay25 and 26 energized the brake magnet MI is maintained energized by aconnection through contacts 31 of relay 26 to door switch 22, whichconnection shunts the contacts 300i relay-25 but the feed for the timerT is interrupted by the contacts 3| of relay 25. Thus switch R, ifenergized, becomes deenergized, whereas switch F is rendered responsiveby a connection from contact t of the timer through contacts 32 of'relay25 and contacts 3'! of relay 26 to door switch 22. Such connections forswitch" F andbrake magnet H! are maintained by the contacts 3'! of relay26 until after contacts 37 upon release of said relay are shuntedthrough the relay contacts 3t and limit switch LS. Thus asaforeindicated switch F and brake magnet Iii-remain energized until bothare deenergized by opening of" limit 1 switch LS after disengagementofcontacts 3'! of relay 26.

We claim:

1. The combination with amotor driven machine, of control means thereforaffording-it periodic reversals and comprising an element actuable todirect stopping, and means under the control of'said element immediatelyto restrict said machine to operation in a single and-predetermineddirection when stopping is-directed, means operated intermittently bysaid machine as parts thereof are repeatedly brought into a givenrelation, and stopping means under' the control of said element to beinactive duringnormal operation of said machine and to be' subject tocontrol by said intermittently operated means when stopping is directedby said element; said stopping means including means alWaysrenderinginefiective for'any influence on" said machine a first coaction of saidintermittently 0perated means and said stopping means but" rena dering arepeat coaction thereof effective for stopping.

2. The combination with a motor driven machine, of control meanstherefor aiiording it periodic reversals and comprising an elementactuable to direct stopping and means under the con.- trol of saidelement immediately to restrict'said machine to operation in a singleand predetermined direction when stopping is directed, means operatedintermittently by said machine as parts thereof are repeatedly broughtinto a givenrel'ation, an electroniagnetically controlled mechaninatemotor operation of said machine and eiiect application of said brakeunder control of said intermittently operated means when stopping isdirected by said element, said stopping means including means renderinga first coaction between said intermittently operated means and saidstopping means of no effect on operation of said machine but effectiveto adjust said stopping means for stopping action including applicationof said brake upon repeat coaction of said intermittently operated meansand said stopping means.

3. The combination with a motor driven machine, of an element operablethereby as parts thereof are repeatedly brought into a given r lation,and means controlling the operation of said machine and comprisingstopping means to stop the machine always with its said parts insubstantially said given relation, said stopping means comprisingelectroresponsive relays and means placing said relay under the controlof. said intermittently operated element when stopping is desired,stopping being dependent upon given conditioning of said relays by saidelement and said element after operation to effect such givenconditioning of one of said relays requiring a repeat operation toeffect such given con ditionin of another of said relays.

4. The combination with a motor driven rnachine, of control meanstherefor affording it periodic reversals and comprising for stopping, afirst relay, a second relay and means to effect given positioning ofsaid relays when stopping is desired, said control means when soposition ing said relays restricting said machine to operation in asingle and predetermined direction until stopped, and means operable bysaid machine in cycles and effective at a predetermined point in onecycle to effect change in position of said first relay and at the somepoint in the next cycle to effect dependently upon the change inposition of said first relay change in the position of said second relayfor stopping.

5. The combination with a motor driven machine, of an element operablethereby as parts thereof are repeatedly brought into given relation, andmeans controlling the operation of said machin and comprising stoppingmeans to stop the machine always with its said parts in substantiallysaid given relation, said stopping means comprising relays andenergizing means therefor to place them under the control of saidintermittently operated element when stopping is desired, stopping beingdependent upon deenergization of said relays by said element and saidelement after operation to deenergize one of said relays requiring arepeat operation to deenergize another of said relays.

6. The combination with a motor driven machine, of a switch operableintermittently by said machine for momentary opening, and control meansfor said machine comprising for stopping, a first relay, a second relayand means to energize said relays and place them under the control ofsaid intermittently operable switch, said first relay beingdeenergizable by the next openof said switch but having contacts whichdisengage only after affording said switch time to reclose and whichmaintain said second relay energized subject to deenergiaation by repeatop eration of said switch.

7. The combination with a motor driven machine, of control meanstherefor affording it periodic reversals and comprising for stopping, afirst relay, a second relay and means to energize said relays whenstopping is desired, said control means upon response of said relaysrestricting said machine to operation in a single and predetermineddirection until stopped, and means operable by said machine in cyclesand efiective at a predetermined point in one cycle to deenergize saidfirst relay and at the same point in the next cycle to deenergize saidsecond relay to efiect stopping, said first relay aifording said secondrelay for a transient period after deenergization of the former amaintaining circuit independent or" said means operable by said machine.

8. A controller for a motor driven machine comprising in combination acontroller to effect power operation of the machine and reversalsthereof, an electrically controlled mechanical brake for the machinehaving control connec tions controlled by said controller to provide forbrake free power operation of the machine in eithe direction, switchmeans having connections with said controller such as to restrictoperation of the machine to a single and predetermined directionimmediately upon a given adjustment of said switch means regardless ofthe condition and direction of operation of the machine when suchadjustment is made, a device having means for operating the sameintermittently and switch means normally free from influence by saiddevice but being subjected to control thereby by the former switch meansupon said given adjustment thereof, the second mentioned switch meanshaving interconnections with said controller such that given adjustmentof the second switch means effects machine stoppin with application ofsaid brake as an incident and the second mentioned switch meanscomprising means necessitating making of said given adjustment of thesecond mentioned switching means in steps respectively dependent uponand efiectable by a first operation and a repeat operation of saidintermittently operable device prior to exercise of any slow down actionby the second mentioned switching means.

JOHN T. KENNEDY. EIVIND U. LASSEN.

REFERENCES CITED UNITED STATES PATENTS Name Date Harvey et al June 9,1942 Number

